The field of the invention generally relates to gas surface burners, and more particularly relates to gas burners that are sealed to the main top to prevent spills from running down through the burner aperture in the main top.
In the typical configuration, the main top of gas range has a plurality of apertures through which the surface burners extend upwardly. For example, the throat of each burner head as it extends through the aperture may have diameter of two inches, and the aperture may be four inches in diameter. With such arrangement, there is a one inch annular concentric opening around each burner throat, and secondary combustion air passes from underneath the main top through this opening. As contrasted with the primary combustion air that is aspirated into the venturi to mix with the fuel before combustion, secondary combustion air is drawn to the flame to support combustion. One drawback of the above described arrangement is the liquid on the main top can run down through a burner aperture thus requiring lifting up the main top to clean underneath. For example, liquid may be present on the main top as a result of a pot boiling over, an accidental spill, or during cleaning of the main top.
Sealed gas burners typically have a flange that is sealed to the upper side of the main top. This arrangement has the advantage of preventing liquid from running down through the burner aperture, and thereby eliminates the need to lift up the main top to clean underneath. However, the sealing of the burner to the periphery of the burner aperture in the main top also seals up the heretofore described path for secondary combustion air. Therefore, sealed gas burners have totally relied on secondary combustion air flowing across the main top through the grates. It has been determined that with this arrangement, there may not be sufficient secondary combustion air to produce favorable flame characteristics, especially when a large pan is placed on the grate. That is, the space between main top and the pan has to be used not only for introducing secondary combustion air, but also for exhausting products of combustion. One prior art approach to providing good flame characteristics is to use taller grates thereby increasing the space between the main top and a pan. However, this approach raises safety concerns in that it may be easier for a pan to tip over. Another approach has been to increase the primary combustion air. However, this approach generally increases the velocity of the fuel/air mixture, and the flame may start to lift off or reach.